feat(ui): add tabbed forms with height validation

- Implement General/Advanced tabs for add/edit forms
- Add terminal height detection with user-friendly warnings
- Add Ctrl+J/K tab navigation and SSH RemoteCommand/RequestTTY fields

internal/ui/styles.go

@@ -33,7 +33,8 @@ type Styles struct {
 	HelpText lipgloss.Style
 
 	// Error and confirmation styles
-	Error lipgloss.Style
+	Error     lipgloss.Style
+	ErrorText lipgloss.Style
 
 	// Form styles (for add/edit forms)
 	FormTitle     lipgloss.Style
@@ -97,6 +98,11 @@ func NewStyles(width int) Styles {
 			BorderForeground(lipgloss.Color(ErrorColor)).
 			Padding(1, 2),
 
+		// Error text style (no border, just red text)
+		ErrorText: lipgloss.NewStyle().
+			Foreground(lipgloss.Color(ErrorColor)).
+			Bold(true),
+
 		// Form styles
 		FormTitle: lipgloss.NewStyle().
 			Foreground(lipgloss.Color("#FFFDF5")).